/*
 * Open Source Physics software is free software as described near the bottom of this code file.
 *
 * For additional information and documentation on Open Source Physics please see:
 * <http://www.opensourcephysics.org/>
 */

package scikit.numerics.ode;

/**
 * AbstractODE provides a common superclass for ODESolvers.
 *
 * @author       Wolfgang Christian
 * @version 1.0
 */
public abstract class AbstractODESolver extends Object implements ODESolver{
   protected double stepSize = 0.1; // parameter increment such as delta time
   protected int numEqn = 0; // number of equations
   protected ODE ode; // object that computes rate

   /**
    * Constructs the ODESolver for a system of ordinary differential equations.
    *
    * @param _ode the system of differential equations.
    */
   public AbstractODESolver(ODE _ode){
      ode = _ode;
      initialize(0.1);
   }

   /**
    * Steps (advances) the differential equations by the stepSize.
    *
    * The ODESolver invokes the ODE's getRate method to obtain the initial state of the system.
    * The ODESolver then advances the solution and copies the new state into the
    * state array at the end of the solution step.
    *
    * @return the step size
    */
   abstract public double step();

   /**
    * Sets the step size.
    *
    * The step size remains fixed in this algorithm
    *
    * @param _stepSize
    */
   public void setStepSize(double _stepSize){
      stepSize = _stepSize;
   }

   /**
    * Initializes the ODE solver.
    *
    * The rate array is allocated.  The number of differential equations is
    * determined by invoking getState().length on the ODE.
    *
    * @param _stepSize
    */
   public void initialize(double _stepSize){
      stepSize = _stepSize;
      double state[] = ode.getState();
      if (state==null){ // state vector not defined
         numEqn = 0;
      } else{
         numEqn = state.length;
      }
   }

   /**
    * Gets the step size.
    *
    * The stepsize is constant in this algorithm
    *
    * @return the step size
    */
   public double getStepSize(){
      return stepSize;
   }

   /**
    * A factory method that creates an ODESolver using a name.
    * @param ode ODE
    * @param solverName String the name of the algorithm
    * @return ODESolver
    */
//   public static ODESolver createODESolver(ODE ode, String solverName){
//      solverName = solverName.trim().toLowerCase();
//      if (solverName.equals("rk4")){
//         return new RK4(ode);
//      } else if (solverName.equals("multistep")){
//         return new ODEMultistepSolver(ode);
//      } else if (solverName.equals("adams4")){
//         return new Adams4(ode);
//      } else if (solverName.equals("adams5")){
//         return new Adams5(ode);
//      } else if (solverName.equals("adams6")){
//         return new Adams6(ode);
//      } else if (solverName.equals("butcher5")){
//         return new Butcher5(ode);
//      } else if (solverName.equals("cashkarp45")){
//         return new CashKarp45(ode);
//      } else if (solverName.equals("dormandprince45")){
//         return new DormandPrince45(ode);
//      } else if (solverName.equals("eulerrichardson")){
//         return new EulerRichardson(ode);
//      } else if (solverName.equals("euler")){
//         return new Euler(ode);
//      } else if (solverName.equals("fehlberg8")){
//         return new Fehlberg8(ode);
//      } else if (solverName.equals("heun3")){
//         return new Heun3(ode);
//      } else if (solverName.equals("ralston2")){
//         return new Ralston2(ode);
//      } else if (solverName.equals("verlet")){
//         return new Verlet(ode);
//      } else return null;
//   }

}

/*
 * Open Source Physics software is free software; you can redistribute
 * it and/or modify it under the terms of the GNU General Public License (GPL) as
 * published by the Free Software Foundation; either version 2 of the License,
 * or(at your option) any later version.

 * Code that uses any portion of the code in the org.opensourcephysics package
 * or any subpackage (subdirectory) of this package must must also be be released
 * under the GNU GPL license.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA
 * or view the license online at http://www.gnu.org/copyleft/gpl.html
 *
 * Copyright (c) 2007  The Open Source Physics project
 *                     http://www.opensourcephysics.org
 */
